Manufacture of ground glass surface on film support



Patented Aug. 7, 1934 I UNITED STATES PATENT OFFIC MANUFACTURE OF GROUNDGLASS SUR- FACE ON FILM SUPPORT Alfred D. Slack, Rochester, N. Y.,assignor to Eastman Kodak Company, Rochester, N. Y., a corporation ofNew York No Drawing. Application January 15, 1932, Serial No. 586,953

12 Claims. (CI. 9170) This invention relates to films of a celluloseperature of'120 F. to 180 F. will normally be a derivative the surfaceof which is rendered transsatisfactory range. lucent and diffusing. Thissurface resembles, in The treatment may be carried out by either imsomerespects, a ground glass surface; it is, for mersing the film, byfloating it on the surface, or example, slightly roughened and capableof takby applying the solution by means of rolls to one 60 ing writingwith an ordinary pencil. or both sides. These methods are all wellknown. The solvent action of-solutions of the thiocya- After treatmentin this solution, the film is nates on cellulose acetate has been knownheredried in warm air when it will be found to have tofore. I have,however, discovered a new effect acquired a translucent and lightdiffusing surwhich these salts may have, not only on cellulose face. 5

acetate, but on other cellulose derivatives. I have Example H found thatby utilizing a solution of a thiocyanate in water to which has beenadded some liquid The procedure is exactly as before but the which aidsin the penetration of the solution in solution in which the film istreated is the film, the salt penetrates the base and on dry- 7o ingwith heat a translucentbase remains. The figigg g ggg gains alkalithiosulfates are also useful in the same 0 fi H h h m1 t I Example III esa s w 1c are use 1n my mven ion are the thiocyanates and thiosulphatesof the alkalies, ggg g gfi f aga'm Is as before m the follow 75 that is,the thiocyanates of sodium, potassium or Parts by weight ammonium, andthe thiosulphates of sodium, po- Sodium thiosulfate 15 55mm ammonium-Glacial acetic acid 10 To a water solution of these salts I add a l1quidAcetone 20 to aid the salts in entering the film. The liquids, waterIII": 55 so anyone of which may be added to the water solutions of thesalts in question, I will define as pen- As s a d a v the degree of t aslu n y may etrating agents. These liquids are, for exam 1 be varied andcontrolled by variations in the conacetone, methyl alcohol, ethylalcohol, ethy centrations of the solutions, by the temperature tate,small quantities of triacetine and 28% amat which the is and by the s5monia. Some of these substances by themselves peratmje and rate, ofdrymg' Any of these may are solvents of some of the cellulosederivatives. be .easlly determmed however by a few trials In myinvention they are all employed in soluia gg z gg fi i g i fifi i is usetions containing water and under these condltions they serve to swell orsoften the surface so ml for a number of purposes one of its pnncipalbeing for leaders for motion picture film inthat they aid in thepenetration of the salts mto use-s the surface layer. which titles ordata relating to the pictures may h fouPwmg examples W111 serve toIllustrate vyh il e lia vfi l lfit t d my invention and its 40 themventlon' application to cellulose acetate, it is to be under- 95Example I stood that I include films of any cellulose ester or The ofcellulose derivative, such as celluether. It is also understood that Iconsider as included in my invention all modifications and figg 15treated wlth the following 501111 equivalents coming within the scope ofthe appended claims. o

Ammonium thiocyanate 20-25 grams What I claim is: Ammonia, 28% 30-50cc. 1. The method of rendering the surface of an Acetone 20-10 cc.extended flexible film of a. cellulose derivative Water to 35-15 cc.translucent and light difiusing which comprises treating the surface ofsaid film with an aqueous The foncentmtlon of the solutlon to be used issolution containing a salt selected from the group determined by thedegree of translucency desired consisting of thiocyanates and t t p. andthis effect is controlled to a great extent not fates of the alkalles ata temperature of not more only by the concentration of the solution usedthan 180 F., and then drying said film.

55 but by the temperature at which itisused. Atem- 2. The method ofrendering the surface of an extended flexible film of a celluloseorganic derivative translucent and light diffusing which comprisestreating the surface of said film with an aqueous solution containing asalt selected from the group consisting of the thiocyanates and thethiosulfates of the alkalies at a temperature of not more than 180 F.,and then drying said film with the aid of heat.

3. The method of rendering the surface of an extended flexible film of acellulose organic derivative translucent and light diffusing whichcomprises treating the surface of said film with an aqueous solutioncontaining a liquid which is a penetrating agent for the film and a saltselected from the group consisting of the thiocyanates and thethiosulfates of the alkalies at a temperature of l20-180 F., and thendrying said film.

4. The method of rendering the surface of an extended flexible film of acellulose derivative translucent and light diffusing which comprisestreating the surface of said film with a hot aqueous solution containinga thiocyanate of an alkali at atemperature of 120-180 F., and thendrying said film with the aid of heat.

5. The method of rendering the surface of an extended flexible film of acellulose derivative translucent and light diffusing which comprisestreating the surface of said film with a hot solution containing aliquid which is a penetrating agent for the film and a thiocyanate of analkali, and then drying said film with the aid of heat.

6. The method of rendering the surface of an extended flexible film of acellulose derivative translucent and light diffusing which comprisestreating the surface of said film with a hot solution containing aliquid which is a penetrating agent for the film and a thiosulfate of analkali, and then drying said film with the aid of heat.

7. The method of rendering the surface of an extended flexible film of acellulose derivative translucent and light diffusing which comprisesnate, and then drying said film with the aid of heat.

9. The method of rendering the surface of an extended flexible film ofcellulose acetate translucent and light diffusing which comprisestreating the surface of said film with a solution containing a liquidwhich is a penetrating agent for the film and a salt selected from thegroup consisting of the thiocyanates and the thiosulfates of thealkalies, and then drying said film.

10. The method of rendering the surface of an extended flexible film ofcellulose acetate translucent and light diifusing which comprisestreating the surface of said film with a hot solution containingacetone'and ammonium thiocyanate, and then drying said film with the aidof heat.

11. The method of rendering the surface of an extended flexible film ofcellulose acetate translucent and light difiusing which comprisestreating the surface of said film with a solution contaning acetone,acetic acid and sodium thiosulfate, and then drying said film with theaid of heat.

12. The method of rendering the surface of an extended flexible film ofcellulose acetate translucent and light difi'using which comprisestreating the surface of said-film with a solution containing sodiumthiocyanate and ammonia, and then drying said film with the aid of heat.

ALFRED D. SLACK.

